Financial planner David Newberry said low income earners already get little or no tax benefits from contributions to their superannuation.

"Super contributions are taxed at 15 per cent, so there are many people who would actually be in a position where the tax rate on their super contributions would exceed ... the tax rate if money was taken as salary or wages," he said.

The low-income super contribution returns up to $500 paid in tax to super accounts of people who have earned less than $37,000 that year.

Marcia Keegan from SGS Economics and Planning said low-income earners could be worse off by tens of thousands of dollars.

"Someone who's earning $35,000 a year for most of their working life is going to retire with 16.7 per cent less superannuation than they otherwise would have, which is quite a hit," he said.

"Only a small proportion of this loss is going to come from a freeze in the superannuation guarantee contribution rates.

"There's going to be a 13 per cent drop resulting from the removal of the low income super contribution."

I think it hits regional areas because it hits low-income earners, which happen to live in regional areas because [they] can't live or afford to live in the metropolitan areas

Financial planner David Newberry

An analysis of the last census data by left-leaning think tank the Australia Institute indicates Nationals' electorates will bear the brunt of the changes.

Mr Newberry, whose practice is in Tamworth, estimates at least 20 per cent of his clients will be affected.

"I think it hits regional areas because it hits low-income earners, which happen to live in regional areas because [they] can't live or afford to live in the metropolitan areas," he said.